As part of this series on Mixed Models, Mary Agyapong shared her analytic pipeline to run a mixed model in SPSS using the mixed command.
Our motivation to run this demo was a common misconception of the definition of mixed/multilevel models as a repeated-measures regression only, originating from the fact that SPSS mixed command can be run without specifying the random effect (such model would be a Generalised Estimating Equation (GEE) model, and not a mixed model).